- April 30, 2004, David J. Bentley Jr., RBS Technologies
Safety must be foremost in all our actions, from the time we awake in the morning until we go to bed at night.
Failure to be alert to the safety aspects of everything we encounter during the course of a day can lead to a problem that has the potential to be disastrous. Everyone has heard considerable information relating to safety in the home and in the car. Safety in converting operations is equally important.
Although you may have heard or read much information on safety, please do yourself the favor of reading this and the next two columns on this subject. A simple reminder may be the factor that saves your life, your sight, your limbs, etc.
In general, the three primary categories involving concerns about safety in the converting industry are heat, pinching nips, and housekeeping. Grouping the issues concerning safety into these three classes makes it easier to address them in our daily actions. Careful attention to each of these three factors almost certainly will ensure you are working in a safe environment.
Arbitrarily, let us consider heat in this column and devote the two following columns to the other items. Please note, however, that all three categories have equal importance.
Generally, heat has use in three possible operations in a converting plant. Some materials require heat before they can be processed on a converting line. These would include hot melt adhesives and coatings, coatings that come in the form of gel lacquers, pellets of resin in the barrel of an extruder, etc. Certain products supplied in solvent or water require heating in an oven after coating to remove the solvent or water from the product. Finally, a heated nip may be necessary in a converting operation, such as the combination of two webs using a laminating adhesive.
The first danger from using heat is that various surfaces can become sufficiently hot to cause burns to people who come into contact with them. People in areas where such operations are taking place must be extremely careful about what they touch. A good practice is to wear gloves and other protective devices that allow operators to avoid contact with the heat.
Operations using heat also can be a potential source of fire. This can happen if an upset should occur in the operation. For this reason, personnel using heat always must be alert to the possibility something might burn.
The other danger when using heat is more subtle. Heating something can cause the release of fumes. Often these fumes are harmful when people breathe them. During the heating of any material, always be certain you know the composition of the vapors being released. Are you simply releasing water vapor? Are you vaporizing solvent? Does the product undergoing heating have the potential to release a toxic isocyanate product? This information normally will be available from the material safety data sheet covering the product.
Heating a hot melt adhesive before its application can release fumes that might be unhealthy for people working in the area. Users must be certain they are exhausting the fumes to someplace where the fumes will not harm workers, or workers must be provided with appropriate breathing devices.
Converting lines that run a coated web through an oven obviously generate vapors; that is the intent of the operation. Users must know the composition of these vapors and take the necessary steps to ensure workers are not exposed to any harmful materials.
Adhesives, inks, and coatings supplied in water often will not emit hazardous vapors during evaporation of the vehicle, but someone always should check the material safety data sheet to be certain this is indeed the case.
Using materials in which the vehicle is a solvent or blend of solvents generally does result in hazardous vapors. Note that these vapors are hazardous to breathe and can burn when exposed to a source of ignition under the correct conditions.
Next month's column will continue to address safety by looking at pinching nips.
David J. Bentley Jr. is a recognized industry expert in polymers, laminations, and coatings with more than 30 years of experience in R&D and technical service. Contact him at firstname.lastname@example.org